Method of rendering leaves of blank-books flexible.



- flexibility renders the books flat opening.-

UNITED v STATES PATENT OFFICE.

LINCOLN CLARK, OF CHICAGO, ILLINOIS.-

METHOD OF RENDERING LEAVES OF BLANK-BOOKS FLEXIBLE.

SPECIFICATION forming part of Letters Patent NO. 645,459, dated March 13, 1900.

v I Application filed January 19, 1900. Serial No. 2,052. (No specimens.)

T0 aZZ whom it may concern:

Be it known that I, LINCOLN CLARK, a citizen of the United States, residing in Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in the Art or Method of Rendering the Leaves of Blank-Books Flexible in the Zone of Flexure, of which the following is a specification.

This invention. relates to a new and improved method of rendering flexible that portion or zone of the leaves of ledgers and other blank-books where the principal flexure occurs when the books are opened and which The patent to Vawter, No. 622,986, describes several ways of obtaining this flexibility; but I believe my method to be not only better but cheaper than any method heretofore practiced.

My invention consists in subjecting the portion of the leaves inwhich the flexibility is desired to the action of the sand-blast,whereby the calendered surface may be broken up or removed sufficiently to obtain just the degree of flexibility desired.

In the practice of the invention I place the sheets upon a moving table, belt, or other support and cover those portions of them which are not to be acted upon with rubber pads or other protecting devices and then pass the same across the path of a mild sand-blast, by

exposed part or zone of the leaves is removed, taking care that only enough of the surface is removed to accomplish the object in View. Both sides of the paper or one only may be treated in this way, as preferred, and if both sides are treated they may be acted upon simultaneously.

I find by actual tests that the paper is ten dered very flexible in this way and without weakening it to any injurious extent, and a book made up of the leaves opens perfectly flat. The treated zones of the leaves are by my process reduced somewhat in thickness, which of course facilitates the flat opening.

While I have specified a sand-blast as a which the smooth calendered surface of the proper means for use in treating the paper, it 1 will be understood that I do not wish to be limited strictly to sand, as other loose abrading materials may be used.

I claim The method of rendering the leaves of blank books flexible in the zone of flexure, consisting in subjecting such zones thereof to the action of a mild sand-blast for the removal of the calendered surface and thinning of the paper, substantially as specified.

- LINCOLN CLARK Witnesses:

ED S. EVARTS, H. M. MUNDAY. 

